Electrical apparatus



Dec. 25, 1928. 1,696,348

W. R. FRAMPTON ELECTRICAL APPARATUS Original Filed Aug. 1. 1922 r fir 2&

' 1 ii J Patented Dec. 2 5, 1928.

UNITED STATES PATENT OFFICE.

WILLIAM B. FRAHPTON, OF LOS ANGELES, CALIFORNIA, .ASS IGNOR TO SOUTHERN CALIFORNIA EDISON COMPANY, OF LOS ANGELES, CALIFORNIA.

ELECTRICAL APPARATUS.

Original application filed August 1, 1922, Serial No. 579,015. Divided and this application filed June 7 1924. Serial No. 718,501.

This invention has to do with electrical apparatus, and has particular reference to an instrument such as a gauge, meter, 1n d1- cator, or the like; involving or including an electrical contact device.

Various instruments, for instance gauges, meters, indicating recording instruments, etc, have, for various reasons, had incorporated or embodied in them, electrical contacts. The contacts ordinarily employed in such instruments are simple wiping contacts in which the cooperating parts are held in cooperative engagement by some form .of resilient means. The frictional resistance of such contact devices materially interferes with the operation of the instruments and makes them more or less unreliable and inaccurate; this being particularly true in the case of instruments that are at all delicate.

It is an object of this invention to provide an effective accurate instrument including an electric contact device.

Another object of this invention is to provide a contact device in a delicate instrument, without materially influencing the operation or accuracy of the instrument.

This application is a division of my copending application entitled Ground detector filed August 1, 1922, Serial No. 579,015. I

The objects and features of my plresent invention will be best and more in y understood from the followin detailed description of a t pical form an application thereof throughout which description reference is had to the accompanying drawings in which Fig. 1 is a horizontal sectional view of an instrument embodying the present invention.

Fig. 2 is an enlarged detailed sectional view taken as indicated by line 2-2 on Fig. 1.

Fig. 3 is a wiring diagram showing a typical arrangement and application of present invention.

This present invention isapplicable to or suitable for embodiment in instruments of various kinds and for various purposes. The invention is not specifically concerned with the manner or means by which the instrument is actuated or the character of the indications or readings of the instrument.

For the purpose of facilitating a full and limited to the instrument being a voltmeter or any other type or variety of electrical instrument. 1 I

I have illustrated in the drawings an instrument 10 in the form of a voltmeter. The voltmeter 10 includes a suitable frame 11 a suitably graduated scale 12, an indicating arm 13, adapted to cooperate with the scale, and operating meansli, for the arm. In this particular instrument the scale 12 is an arcuate scale located at the front of the instrument immediately behind a suitable transparcnt part 15. The scale 12 is supported from a suitable stationary part of the instrument by means of brackets 20. The arm 13 is mounted to move or swing in a horizontal plane, and is provided at its outer end with a head 16 adapted to cooperate with the scale. The operating means 1 1 for the arm is connected in a suitable circuit carried by a conductor 19. The means 14 is such as tobe actuated by the current carried by the conductor 19, so that it operates the arm 13.

The instrument is further provided with adjustable means for limiting or sto ping movement of the arm 13. The form 0 stop means'illustrated includes a stop part 21 having one end connected to one of the brackets 20, and its other end in position to engage and stop the arm 13. The last mentioned end of the stop part 21 may be adjusted or varied as to position by a screw 23 carried by bracket 20.

The contact device provided by this invention includes, generally, a movable contact 25 and one or more stationary contacts 26. The movable contact 25 is operatively connected with the arm 13 of the instrument. 'In the preferred arrangement the contact 25 is carrieddirectly by the arm 13, and is in the form of a bar or pin. The contact is carried by the arm in a vertical position and preferably so that it can be adjusted vertically. I have illustrated the contact 25 slidably carried in a boss 27,

provided on the arm, and have shown a set screw 28 tor setting the contact in the desired position in the boss.

In the form of the invention illustrated in the drawings there is a plurality of stationary contacts 26, arranged to be engagei'l by the lower end of the contact upon the contact being carried or moved by the arm 13. In accordance with this invention each contact 26 is formed by a body or elobule of mercury carried in an indentation 29, in a suitable support 30. The support 30 is arranged horizontally, and the indentation 29 and globule of mercury are proportioned so that the mercury stands or proje'ts somewhat above the s pport. The support is spaced below the lower end of the Contact 25 so that the contact will not one th support 30 but will engage the mercury contacts. In a. case where there are several contacts 26, there may be a. si g le or common support 30 provided the proper points or intervals with the indentations to carry the globules of mercury: the indenta tions being located so thatthe globules of mercury are in the path of the contact IValls extend upwardly from or around the support 30 to form a container for oil. or the like. In the particular container illustrated in the drawings the walls extend upwardly from the supportso that the support forms the bottom of the container. Oil or other suitable fluid is tilled into the container to completely submerge the globules of mercury.

The support 30 and the parts which form the container for the oil may be supported in the proper position in any suitable manner. In the drawings this support 30 is provided with suitable supporting brackets connected to a stationary part of the instrument by means of screws 36.

The necessary electrical connections may be made by or through the mechanism just described in various manners. In the arrangement illustrated in the drawings contacts and 26 cooperate to control a relay It. The relay R is connected with one side of a battery B, or other suitable source of energy, by a conductor 40. The other side of the battery B is connected with the relay through a conductor 41, the contacts and 26 and a conductor 42. The conductor 41 extends from the battery to the frame of the instrument which is grounded with the arm 13 of the instrument. The conductor 42 extends -from one of the brackets to the relay. The supporting brackets 35 for the support 30 are insulated from the instrument by means of insulation 4-4. arranged between the brackets 35 and the part ot the instrument to which the brackets are connected. The rel: y may be arranged and connected to control any desired circuitor apparatus, for instance, it may be arranged to control an alarm cir uit as in the ca. set forth in the above mentioned (vi-pending application.

From. the foregoing description. it lieved that the operation ol the app. will be fully understood. mentor vohjmetei 1H actuated so that the arm 13 is moved the contact E moved into and outo'l engagen'ieni' or contact with the merrury contacts 26. The moving of the contact into and out oi engagement with the contact 26. makes and breaks the relay circuit. In the case of several contacts 26 such as I have illustrated in the drawings, the relay circuit will be made and broken several times during: the nmvemeut oil the arm 13, through its full travel. It it desired to have the relay circuit held open or closed when the arm of the instrument is fully actuated the stop 21 may be adjusted to stop the arm 13 in the proper position with relation to one of the meni'urv contacts 26.

It will be apparent that the contact .25 will move over or through the mercury o tacts 26 with a i'uiuimum amount of triclion. and that the oil in which the contact 26 are submerged will prevent or at least lLhIlI'HIZQ arcing.

Having described only a typical form and application of my invention I do not wish to limit myself to the parth-ular details herein above set forth, but wish "lo reserve to myself any changes or variations that may appear to those szilled in the art and "fall within the scope of the following claim.

I claim:

In combination, an instrument having a horizontally movable indicating part, an open topped container arranged below the indicating part, the bottom of the container having a depression, a globule 0t menrury carried in the depression to project above the bottom of the container, fluid in the container covering the mercury, and a contact carried by the indicating part to extend into the container to clear the bottom of the container and cooperate with the mercury.

In witness that I claim the foregoing I have hereunto subscribed my name this 29th day of April, 1924.

is be ratus When the instru- WILLIAM R. FRAMPTON. 

